[i]Two vertices of a rigid triangle slide along two fixed arms in the plane. What is the locus of the third vertex?[/i]
Sometimes Geogebra is like having a master geometer in one's back pocket.
If the two arms are fixed at a right angle, and C is in a straight line with AB, we have Archimedes' (?) Trammel.
A working model is here: [url]http://www.geogebratube.org/material/show/id/71230[/url]
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This is problem # 47 in Heinrich Dorrie's [i]100 Great Problems of Elementary Mathematics[/i].
